JPS5994412A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To flatten the surface of a single crystal Si film on an insulating film while obtaining the single crystal Si film in the same orientation as an Si substrate by accelerating Si ions toward the insulating film while keeping the temperature of the Si substrate at 600 deg.C or more and evaporating the Si film on the insulating film and the exposed section of the substrate. CONSTITUTION:The single crystal Si substrate 1 with a (111) face is coated with an SiO2 film 2, and the film 2 is removed at every 4mum width at the pitches of approximately 50mum and a plurality of windows 3 are bored. The substrates 1 are arranged in a bell jar 4, an inside thereof is evacuated, while the films 2 are directed downward, and the substrates 1 are heated at 600 deg.C or more by a heater 6 connected to an AC power supply 5. Electron rays are irradiated to an Si source 8 in a crucible 7 set up to the lower section of the bell jar 4, and the Si is evaporated, and ionized by a cathode 10 and an anode 10' as thermoionic impact means. A shutter 12 is opened, Si ions are accelerated by using an accelerating means 11, and Si ions are attached on the films 2 and the exposed sections of the substrates 1. Accordingly, the Si film 13, the crystalline direction thereof is the same as the substrate 1, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device in which a single crystal silicon film is formed on an insulating film, and an object of the present invention is to make it possible to uniformly form a single crystal silicon film over the entire surface of the insulating film. In general, three-dimensional circuit elements in which devices are three-dimensionally formed within a single-crystal silicon chip via an insulating film and on an insulating film are used to increase the degree of integration and speed of integrated circuits. So-called 501 elements, in which devices are formed on single-crystal silicon films, are attracting attention, but when manufacturing either the three-dimensional circuit elements or SOI elements, it is necessary to form a single-crystal silicon film over the entire surface on an insulating film. There is a need to.

Conventionally, a method has been used in which a silicon film is formed over the entire surface of the insulating film and then only the silicon film is crystallized by heat treatment with laser light, or by removing a part of the insulating film on a single crystal silicon substrate. After forming an exposed window on the substrate and forming a silicon film on the insulating film and the exposed substrate, only the silicon film is melted by a laser beam, and the silicon film is sequentially removed from the substrate surface of the window. A solidification method has been implemented, but in the former case, sub-grains are formed in the silicon film at about 20 μm by 9 inches,
The silicon film does not become a perfect single crystal, and in the latter case, it also does not become a perfect single crystal, and there is a drawback of poor reproducibility.

Further, an insulating film made of silicon dioxide is formed on a single crystal silicon substrate, a part of the insulating film is removed to expose the substrate, and the insulating film and the exposed A method has been implemented in which a single crystal silicon film is formed on the substrate and the exposed silicon film on the substrate is grown in a direction parallel to the surface of the insulating film. 2 μmu
Then, in the vapor phase growth process or the evaporation process, the lateral single crystal growth of the silicon film on the insulating film from the exposed substrate is also about 2 μm; It is not practical to form a single crystal silicon film to a uniform length.

This invention was made with the above points in mind,
An insulating film is formed on a silicon substrate, a part of the insulating film is removed to form a window in which the surface of the substrate is exposed, the temperature of the substrate is maintained at 600° C. or higher, and silicon ions are generated by an accelerating means. A single crystal silicon film is deposited on the insulating film and the exposed substrate by accelerating toward the insulating film, and a single crystal of 10 μm or more is deposited on the silicon film on the window in a direction parallel to the surface of the insulating film. The present invention provides a method for manufacturing a semiconductor device characterized by using growth.

Therefore, according to the method for manufacturing a semiconductor device of the present invention, the temperature of the silicon substrate is maintained at 600° C. or higher, silicon ions are accelerated toward the insulating film, and single crystal silicon is deposited on the insulating film and the exposed substrate. By depositing the film, the surface of the silicon film on the insulating film can be made substantially flat, and a single crystal silicon film having the same orientation as the substrate can be formed over the entire surface of the insulating film.

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

Now, to explain the manufacturing process, the upper surface of the single-crystal silicon substrate (1), which is a surface with a Miller index of (111), is thermally oxidized to form an insulating film (2) made of silicon dioxide with a thickness of 1 μm on the upper surface. , the insulating film (2) is removed with a 50-μm pitch at a width of 4 μm to form a plurality of exposed windows (3) on the substrate (1), and a bell jar (4) whose interior is kept in a vacuum is formed. A substrate (1) is placed in the upper part of the chamber with the insulating film (2) facing down, and the substrate (1) is heated and maintained at 800° C. by a heater (6) connected to an AC power source (5).

The crucible (
7) is irradiated with an electron beam to evaporate it, and the cathode (10) and anode αα of the thermionic impact means (9) provided above the crucible (7) in the bell jar (4) are evaporated. An ionizing current of 300 mA is passed between the two to ionize the silicon vapor, and the accelerating electrode of the accelerating means αυ provided above the thermionic bombarding means (9) in the bell jar (4) is
A voltage of minus 7 KV is applied to accelerate the silicon ions upward, and a shutter (2) provided between the acceleration means αD and the substrate (1) is opened, and the accelerated silicon ions are transferred to the insulating film (2). and exposed substrate (1)
In this so-called ion deposition process, an east crystal silicon film αJ having a thickness of 2 μm is deposited at a deposition rate of 0.3 μm/min.

At this time, since the silicon ions that adhere to the surface of the insulating film (2) have large energy, even after the silicon ions adhere to the insulating film (2) and become atmospherically neutral silicon atoms, the Silicon atoms move on the insulating film (2) and reach the substrate (1) exposed in the window (3),
Single crystal silicon grows on the insulating film (2) from the surface of the substrate (1) in 3) in a direction parallel to the surface of the insulating film (2).
μ! n or more.

In addition, when we experimentally analyzed the crystallinity based on the electron beam diffraction image of the silicon film 03) on the insulating film (2), we found that the substrate consists of a single crystal grain with a Miller index of (111) where Kikuchi lines can be seen. The result was that it was a perfect single crystal with the same crystal orientation as (1).

According to the embodiment, the silicon substrate (1)
While maintaining the temperature at 800°C, which is higher than 600°C,
By accelerating silicon ions toward the insulating film (2) and depositing a single crystal silicon film (13) on the insulating film (2) and the exposed substrate (1), a silicon film on the insulating film (2) is formed. The surface of αJ can be made almost flat, and the single crystal silicon film (2) can be uniformly formed over the entire iC surface on the insulating film (2), making it extremely suitable for the formation of tertiary element elements and SOI elements. It is useful for

Furthermore, since the surface of the silicon film (13) is a mirror surface,
It is possible to provide a semiconductor element which is extremely practical and has excellent controllability and reproducibility.

Furthermore, since the temperature of the substrate (1) was maintained at 800° C., autodoping can be prevented from occurring.

In the above embodiments, the insulating film (2) is made of silicon dioxide, but the present invention can be implemented in the same manner even if it is made of an amorphous insulating material such as silicon nitride or aluminum oxide.

In addition, by appropriately changing the temperature of the substrate (1) and the ionization conditions of silicon, single crystal silicon was
n T-pixel growth can be performed.

[Brief explanation of the drawing]

The drawings show one embodiment of the method for manufacturing a semiconductor device of the present invention, in which FIG. 1 is a cutaway front view of an apparatus for manufacturing a single crystal silicon film, and FIG. 2 is a cutaway front view of a part of the manufactured semiconductor device. It is a diagram.

Claims (1)

[Claims] (2) An insulating film is formed on a silicon substrate, a part of the insulating film is removed to form a window in which the surface of the substrate is exposed, and the temperature of the substrate is maintained at 600°C or higher, and an electric field is used to accelerate the process. By accelerating silicon ions toward the insulating film and depositing a single crystal silicon film on the insulating film and the exposed substrate, the epitaxial growth of silicon from the window is such that the direction parallel to the surface of the insulating film is perpendicular. A method for manufacturing a semiconductor device, characterized in that a single crystal silicon film having the same crystal orientation as that of the substrate is formed on the insulating film by taking advantage of the fact that the direction is more than 5 times more dominant than that of the substrate.